Reducing Pyrocat Hd Stain

[chrisf]

I over developed some negatives and was wondering if there is a way to remove the stain, since it is proportionally higher in the high values I figured this might help.

I used Pyrocat Hd and contact print on Lodima.

thanks,
chris

 

[Nicholas Lindan]

Once the stain forms and polymerizes it is very, very permanent. You can get rid of the silver and leave the stain behind, though.

 

[hrst]

Once the stain forms and polymerizes it is very, very permanent. You can get rid of the silver and leave the stain behind, though.

It makes sense. Then, is it just a legend that wrong type of stop and fix (too acid) reduces stain? This seems to be "common knowledge" among some people...

 

[Ian Grant]

Well fixing in Hypam doesn't affect the stain at all, nor does stop bath. However an issue with stop bath and developers using carbonte is a higher risk of pinholes, so a weaker stop bath is a good idea.

It's a bit like the myth that bathing the film in the spent developer after fixing will improve the stain, sure it will as it's oxidised more it stains more but not proportionally and can be uneven. It just like adding base fog

Ian

 

[nworth]

Since the density is silver plus stain, a proportional reducer may still help.

 

[Cor]

seem to recall that it is possible to remove/reduce the stain with a solution with potassium permangate..have to dig dep..found it!
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Here is the Kodak S6 formula for removing of stain:

Stock solution A:
Potassium parmanganate 5.2g
Cold water to make 1l

The permanganate has to be dissolved completely to avoid spots on the
neg.

Stock solution B:
Cold water 500ml
Sodium chloride 75g
Sulfuric acid, conc. 16ml
Cold water to make 1l

Caution: Never put the water into the acid, it will boil up!

Stock solution C:
Sodium bisulfite,
1% soilution, this means 1g for 100ml water

1. Harden the film (2-3min) in a hardener solution like 5-10% glyoxal
2. Wash for 5min
3. Bleach in equal amounts of A and B for 3-4min,
the mix is of short shelf life
4. After bleaching put negative in solution C until
all stain is removed
5. Wash thoroughly
6. redevelop under 100W bulb in a non staining developer of low alkali
like D72 dilution 1:2. D76 does no good because of it´s high sulfite
and low alkali which would dissolve the silver image

I did use this formula successful with some overstained Pyro negs a
couple
of times.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Good luck,
(never used it myself, just saved a note
Cor

 

[Ian Grant]

Chances are Chris that you can print through it. The stain being a dye acts as a filter, it's nowhere near as bad as heavy silver density,

Ian

 

[Nicholas Lindan]

seem to recall that it is possible to remove/reduce the stain with a solution with potassium permangate.

Learn something new - ignore my previous post ... I wonder what permanganate bleach does to the tanning effect of pyro - does the negative still have a 3d profile to it?

* * *

On the subject of stop and fix (if I don't put my foot in it, again): the stain is formed when the developer is oxidized in the process of developing a silver grain. Over a period of minutes this oxidized developer polymerizes with the gelatin both staining and tanning it. Sulfite and low pH interfere with the polymerization, carbonate accelerates it. Once the stain is fully formed it isn't effected by sulfite, and it is OK to use a hypo clearing solution. Often the negative is bathed in the used developer after fixing to make sure the polymerization is finished - I haven't tried it, but a carbonate bath after fixing may work better.